Neon’s mother Sally, 37, from Brighton, East Sussex, is opposed to further surgery.

The case hit the headlines earlier this month when Ms Roberts and Neon briefly disappeared, although they were later found in Sussex, with the judge taking the unusual step of naming those involved to help locate them.

Ms Roberts told the family division of the High Court she wanted more opinions before Neon underwent more surgery.

‘I feel I need more expert opinion on it before proceeding,’ she said.

But a doctor told the court the tumour could spread and that it was ‘highly likely’ Neon would die within a ‘relatively short period’ if surgery was not carried out.

The judge had also been asked to rule on whether Neon should undergo radiotherapy treatment after surgery, which Ms Roberts is also opposed to.

Mr Justice Bodley will hear more argument on the radiotherapy issue in court on Thursday.

Doctors have said Neon could die within months if he does not undergo radiotherapy treatment.